Ooku: The Inner Chambers volume 9 features story and art Fumi Yoshinaga.

Yoshimune brought many changes to the inner chambers in her time as shogun, and now even after death she brings another: the men of the Inner Chambers must study Western learning and discover a cure for the Redface Pox. For if Japan can't increase the male population, it's only a matter of time before a foreign power discovers their secret and invades!